problem with soldering rooster esc

[SuperDutyScaler]

my yellow and blue motor leads are too short for my king hauler, so i tried to add longer motor leads tonight and i cant get the factory lead to melt of the rooster? do i have to remove the purple heat sink first or does novak use special high heat lead from the factory? and no im not going to add a length to the end of the factory wires, soplease dontpost that option.